28 MOTIONS OF PLANTS. IMPORTANCE OF [INTROD. 



moved. Amongst the most interesting examples of these move- 

 ments are those of the Mimosa pudica, the Dionaa muscipula, and 

 the Berberis. 



III. It is the province of Physiology to investigate the ways in 

 which the functions of living beings are effected ; and this investiga- 

 tion naturally involves the examination of their mechanism, of the 

 chemical constitution, and of the properties of their component tex- 

 tures. The study of Anatomy must always accompany that of Phy- 

 siology, on the principle that we must understand the construction 

 of a machine before we can comprehend the way in which it works. 

 The history of physiology shews that it made no advance until the 

 progress of anatomical knowledge had unfolded the structure of the 

 body. There is so much of obvious mechanical design in the inti- 

 mate structure of the various textures and organs, that the disco- 

 very of that structure opens the most direct road to the deter- 

 mination of their uses. That kind of anatomy which investigates 

 structure with a special view to function may be properly designated 

 Physiological Anatomy. 



A correct physiology must ever be the foundation of rational 

 medicine. He who is ignorant of the proper construction of a 

 watch, and of the nature of the materials of which it is made, could 

 not find out in what part its actions were faulty, and would there- 

 fore be very unfit to be entrusted with repairing it. In medicine, 

 the first step towards the cure of disease is to find out what the 

 disease is, and where it is situated (diagnosis). Without a know- 

 ledge of the offices which various parts fulfil in the animal O3conomy, 

 our search to determine what organ or function is deranged must be 

 most vague and indefinite. Pathology is the physiology of disease ; 

 and it is obvious, that no pathological doctrines can command con- 

 fidence, which are not founded upon accurate views of the natural 

 functions. It is also certain that improvements in pathology must 

 follow in the wake of an advancing physiology. 



The practice of medicine and surgery abounds with examples 

 illustrating the immense benefits which physiology has conferred 

 upon the healing art. The great advance which has been made of 

 late years in the pathology of nervous diseases, is mainly owing to 

 the discoveries of Bell, and many others, in the functions of vari- 

 ous nerves, and the general doctrines of nervous actions. We may 

 instance the case of the facial nerve the portio dura of the seventh 

 pair. It was supposed formerly that this nerve was the seat of that 

 painful disease, called tic douloureux, and section of it has been 

 performed for the relief of the patient. It is now known that this 



